Telephone system



A 2H, 193$. V, K 2,038,222

TELEPHONE SYSTEM Filed June' 26, 1935 OTHER HOLJ MA GNETS lNVENTOR G l K/NG A'TTO NE) L L n Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application June 26, 1935, Serial No. 28,410

3 Claims.

This invention relates to automatic telephone systems and particularly to improvements in registering mechanism for digits.

An object of the invention is to improve and simplify circuit arrangements used in connection with cross-bar switches as registering mechanism.

Heretofore systems have been provided in which cross-bar switches have been used for registering digits. In these systems a digit was registered by the operation of the desired selecting magnet followed by the operation of a holding magnet when the recording on a set of counting relays of a series of impulses representing the digit was completed. Cross-bar switches have also been used as selectors and connectors Where, in the case of a selector, the selecting magnets were operated and released by succeeding impulses in the digit dialed until the last impulse in the digit was reached when the corresponding selecting magnet was operated and then maintained operated, while the holding magnets were operated automatically in succession to hunt for an idle trunk. When a switch was used as a connector both the selecting magnets and the holding magnets were controlled by the tens and units digits respectively in the same manner as the selecting magnets were controlled when a switch was used as a selector.

. This invention is applicable to a registering system using cross-bar switches. The arrangement for registering digits includes a pulsing relay and a circuit comprising several relays responsive to series of impulses received from the pulsing relay for operating and releasing selecting magnets in succession, one for each impulse, and for looking the selecting magnet operated by the last impulse in each series received and a similar circuit arrangement responsive at the end of each series of impulses for operating and holding operated a succeeding holding magnet and restoring the selecting magnet locked by the corresponding series received. The same type of circuit arrangement is used for the control of both the selecting magnets and the holding magnets and comprises in general two relays for each circuit. In the case of the selecting magnet control the two associated relays are operated for every odd impulse and released for every even impulse, and in the case of the holding magnet control the two associated relays are operated after every odd digit and released after every even digit.

The invention has been illustrated in the accompanying drawing, in which a system is represented as comprising a cross-bar switch SW, used as a register, with its selecting magnets S1 to S10 and holding magnets H1 to H4 located immediately to the left and bottom thereof respec tively. This system also shows a receiving pulse trelay l6 actuated by the subscribers dialing device in subscriber set A, which for the purpose of this description may be assumed to have been connected over line l2 to pulse relay 10 via a line finder or line switch, not shown, control relays l3 to IE for operating the selecting magnet in accordance with the digit number dialed, control relays I! to 2| for operating the holding magnet for each digit dialed, a digit control switch 22 for connecting a sending pulse relay 24 to cross-points on the switch SW in transmitting the recorded subscribers number and release relay 26 for wiping out the record after it has been transmitted to the connecting switches.

The cross-bar switch SW indicated in the drawing may be that of any mechanism having equivalent selecting and holding magnets for operating contacts in the bank of the switch. More specifically, reference may be had to the Patent 2,021,329 to J. N. Reynolds, of Nov. 19, 1935, in

which such a switch is described. For the purposes of this description it has been elected to show a switch having the customary ten rows of contacts high but only four instead of the usual ten rows wide. Also, for simplicity each crosspoint is represented by one set of make contact springs but it will be readily understood that other spring combinations could be provided. Normally, all contact springs are unoperated but when one of the holding magnets operates at the time one of the selecting magnets is in an operated condition, then the contact springs at the corresponding cross-point will close and remain closed as long as the holding magnet remains operated, even though the selecting magnet does immediately release. Other contact springs in the same vertical row with the holding magnet, therefore, remain in a normal position and cannot be closed by their corresponding selecting magnets as long as the holding magnet in that row remains operated. This mechanism, as shown, registers four different digits, one on each row of contacts controlled by its corresponding holding magnet in a manner presently to be described.

Assuming now, for example, that a three digit number such as 454 is to be registered, it will be shown how relays [3, I4, [5 and 16 function on the dialing of the first digit to cause each of selecting magnets S1 to S4 to operate and release in turn for each pulse delivered by relay II]. On the fourth pulse of the first digit as S4 selecting magnet operates the holding magnet H1 operates to lock in an operated position the corresponding contact springs at the cross-point 4 in the first row of bank contacts. It will also be shown how relays l1, l8, I9, 20 and 2| function to control the operating ground for the holding magnets H1 to H4. In the example chosen, after the number 4 representing the first digit has been recorded by the operation of hold magnet H1, the ground circuit is shifted to the magnet H2 so that when the next digit 5 has been dialed the H2 magnet will be operated and thus operate contact springs 21 in the second row of bank contacts. The ground circuit is then shifted to the hold magnet H3 so that it may be operated to function contact springs 28 after the last digit 4 has been dialed. In this manner any number of impulses may be registered on switch SW dependent only on the capacity of the bank to carry the required contact springs.

Upon completion. of registration, the register circuit may be made to function in any one of a number of well-known ways to step the control switch 22 with its magnet 23 for successively connecting the sending pulse relay 24 to leads 36 one at a time, thence to interrupter leads 31 depending on the particular set of contact springs in each row that is operated. Itwill be readily understood that the first one of the interrupter leads 3! at the top of the switch will always be capable of emitting one pulse continuously at intervals, the next lead two pulses and so on to the bottom lead which emits ten pulses. The sending pulse relay 24 will therefore follow the pulses of the lead to which it is connected and under the control (not shown) of the register circuit will function to extend the subscribers talking connection in any well-known manner through connecting switches, not shown, to a called subscriber station.

When'a subscriber calls, the lifting of the telephone receiver from its hook closes the circuit in the' usual way through a line relay, not shown, at the central oflice. If as assumed, the telephone system employs line finders for making connection with a subscriber sender and register circuit, operation of said line relay starts an idle line finder circuit to hunting for and'connect the calling line with an idle subscriber sender and sender register circuit. As these equipments are well-known in the art they have not been shown and it will therefore be assumed that when the subscriber starts dialing the number of the wanted party, the pulsing or subscribers loop circuit is connected as shown in the drawing through leads I2 to the pulse relay III.

The manner in which the operation of pulse relay I0 is registered on the cross-bar switch SW will now be described. A circuit through the windings of pulse relay ID to* battery and ground is now closed by the subscriber over the subscribers line causing said relay to operate and in turn operate relay II which connects direct ground to the top and bottom armatures of relay I0 and is sufficiently slow in releasing to'r-emain operated during the open intervals of the subscribers dial. The subscriber'upon dialing the first digit 4 of the number 454, for example, causes pulse relay IE! to release and reoperate four times. On its first release ground is applied by the top armature to slow-release relay I! which operates .and remains operated as long as the pulses continue in any digit dialed. Relay H in turn operates relay I8, the function of which will later be described. The lower armature 36.

of relay I0 on its first release closes a circuit starting from the ground on lower armature and front contact relay II, armature 3|) and back contact relay I0, lead 3|, armature 29 and back contact relay I6, lead 32, back contact and armature of relay I3 to battery through relay I5. Relay I5 in operating connects at contact 33 a locking circuit for itself through top: winding of relay I6 and ground over lead 34 at bottom front contact relay I8. Current, however, does not flow in this latter circuit until pulse relay I0 reoperates. In the meantime, ground on the top armature relay I5 causes selecting magnet S1 to operate over a path traced from ground through the top front contact relay I5, armature 38 of relay I4 and its back contact, through winding of S1 magnet to battery. Operation of selecting magnet S1 prepares a path at its right front contact for later operating selecting magnet S2, otherwise it'has no function at this time. At the end of the first dial pulse relay I0 reoperates breaking ground at armature 30 to armature 29 of relay I6. This ground path having acted as a shunt on the top winding of relay I6 now allows the latter relay to operate. Relay I6 at its top armature connects ground through the top winding of relay I4 to battery, causing it to operate. Relay I6 at contact 39 supplies. a holding ground for selecting magnet S1 so it will not release when relay |4 operates and breaks the S1 operating circuit through armature 38 previously traced. Relay I6 at armature 29 also prepares a circuit from battery through relay I3, lower winding relay I6, and armature 29 over lead 3| to bottom back contact of pulse relay II] which at the moment is operated. Thus at the end of the first of the four pulses in the first digit reilays I 4, I5 and 'I6 remain in an operated position and relay I3 in normal position. Selecting magnet S1 also remains operated.

At the beginning of the second pulse when relay I6 again releases, ground on bottom armature 3B of relay I0 is connected over lead 3| through bottom winding relay I6 which is operated at this time, lead 35 to winding relay I3 to battery. This path continues to hold relay I6 operated and operates relay I3 which opens the circuit for relay I5. Relay I5 releasing, connects ground at its top back contact to lead 40, thence through the right front contact on selecting magnet S1 to winding and battery on selecting magnet S2 causing the latter to operate and look over the left front contact to leads 4| and 42, contact 43 on relay I5, lead 44, contact 45 and armature 46 on relay I4, lead 34, to ground on bottom contact of relay I8. Relay I5 at contact 33 opens the circuit of the top winding of relay I6 but the bottom winding continues to hold this relay operated. Nothing further happens until relay I 0 reoperates when it removes ground at its bottom armature 33 from lead 3|, armature 29 and bottom winding of relay I6, thereby releasing both relays I3 and I6. Relay I3 at its top break contact and relay I6 at its armature 29 and back contact prepare a path over lead 3| for the next pulse. Release of relay I6 at contact 39 opens locking ground for selecting magnet S1 causing the latter to release. Removal of ground on top make contact relay I6 opens circuit through top winding relay I4 but the latter does not release until all pulses in the digit have been sent since it is now held operated from battery through its lower winding, contact 45 and armature 46 through lead 34 and ground at front contact relay I8. Release of relay I6 also connects lead 42 to lead 5| at back contact 52 relay I6 so that when on the next pulse relay I5 operates and opens contact 43'the selecting magnet S2 will remain operated. Thus at the end of the second of the four pulses in the first digit, relay I4 remains operated and relays I3, I5 and I6 remain normal. Selecting magnet S2 also remains operated.

At the beginning of the third pulse when relay IIl releases, ground on bottom armature 30 and back contact relay I6 is connected over lead 3|,

armature 29 and back contact relay I6, lead 32, back contact and armature relay I3 to battery through relay I5. This path is identical with that traced for the first pulse and likewise results in the immediate operation of relay I5 and the later operation of relay I6 after the pulse relay Ill reoperates. Relay I5 operating causes selecting magnet S3 to operate over a path traced from ground on top armature and front contact relay I5, armature 38 and front contact relay I4, lead 48, right front contact on selecting magnet S2, winding of selecting magnet S3 to battery. The left front contact on the magnet S3 closes a looking path for itself over lead 49, front contact 50 on relay I5, lead 44, contact 45 and armature 46 of relay I4, lead 34 to ground at relay I8. When pulse relay Ill reoperates, the direct ground on lead 3| for holding relay I5 operated is replaced by the ground path through top winding relay I6 which operates as previously described in connection with the first pulse. Relay I6 operating opens back contact 52 which opens the ground path previously traced for holding the selecting magnet S2. Thus at the end of the third of the four pulses in the first digit relays I4, I5 and I6 remain operated and relay I3 remains normal. Selecting magnet S3 also remains operated.

At the beginning of the fourth pulse relay I releases causing the operation of relay I3 and the release of relay I and operation of selecting magnet S4 and the later release of relays I3 and I6 in a manner identical with that described above for the second pulse. Thus at the end of the fourth pulse, relays I0 and I4 remain operated and relays I3, I5 and I6 normal. Selecting magnet S4 also remains operated. This being the last pulse in the first number 4 of the three digit number 454, a short interval elapses before the subscriber starts sending the second digit. In this interval relay I1 releases, thereby releasing relay I8. The latter relay, however, is sufficiently slow to release to permit relay I9 to operate over a path traced from ground on back contact and armature 53 of selecting magnet S1, lead 54, top front contact relay I8, lower armature and back contact relay II, lead 55, contact 56 and winding of relay I9, resistance 51 to battery. Relay 29 does not operate at this time due to the ground on lead 55 being connected direct to the upper armature and back contact relay 2D to resistance 58 which path is in parallel with the path from lead 55 traced through contact 56 or from ground on armature 68 of relay I9, lead 59, winding relay 2D to the same resistance, 58. Relay I9 thus being operated provides a locking circuit for itself on armature 65 over lead 6| from the back contact 62 of relay 26 to ground.

The operation of relay I 9 at its lower armature connects ground to the top armature and back contact relay 2!, thence through the winding of holding magnet H1 to battery. Holding magnet H1 thereupon operates and at its bottom make contact closes a locking circuit for itself to ground on top back contact and armature of relay 26. Contact springs 4 in the bank of crossbar switch SW are thus caused to operate and, as reviously described, the operation of other selecting magnets in recording the succeeding digit numbers will not cause any other contacts in the same vertical row for the holding magnet H1 to operate. Slow relay I8 finally releases and opens ground at the bottom armature from lead 34 thereby causing relay I4 to release followed by the release of selecting magnet S4 and restoring of this portion of the circuit to normal, preparatory to the dialing of the next digit. Release of relay I8 also opens the ground path over lead 54 so that winding of relay 20 is no longer shortcircuited by the circuit through lead 55 and top break contact on relay 20. The latter relay thus operates and both relays I9 and 20 continue to be held by the ground at armature 60 of relay I9 until the end of the next digit is dialed by the subscriber. Relay 20 operates relay 2| which prepares a path for operating succeeding holding magnets H2 etc. Relay 2| remains operated until the complete number is dialed.

The subscriber on dialing the second digit 5 of the number 454 in the example causes pulsing relay ID to operate and release five times. On its first release, ground at its top back contact closes the circuit for again operating relay I I and in turn relay I8, both of which remain operated until the five pulses are sent by the subscribers dial. The first four out of the five pulses from the dial control pulse relay I0 and associated relays I3 to I6 in the same manner as described above for the first digit 4. At the end of the fourth digit therefore relays I3, I5 and I6 will remain normal with relay I4 and selecting magnet S4 operated. At the beginning of the fifth pulse relay I 0 releases causing the operation of relay I5 and later the operation of relay I6 over the same paths previously traced in connection with the first pulse of the digit 4. Relay I 5 operating closes ground at its top make contact to a path traced over armature 38, and front contact of relay I4 to lead 48, thence through right front contact to a selecting magnet S4 to the winding and battery on selecting magnet S5. The latter magnet upon operating provides a locking circuit for itself at its left front contact over lead 49, through make contact 50 on relay I 5, lead 44, to ground at contact 45 on relay I4. Later, as pulse relay I0 reoperates, relay I6 operates and at its back contact 52 breaks the ground circuit, over lead 5 from relay I4, to lead 4I, thereby releasing selecting magnet S4. The net result, therefore, of the five impulses from the subscribers dial is to get selecting magnet S5 in an operated position. At the end of these pulses the relay I'I releases and closes a ground path for causing relay I9 to release. This path is traced from ground on back contact and armature 53 of selecting magnet S1, over lead 54, top make contact on relay I8, bottom break contact on relay I1, lead 55, through top armature and front contact relay 20 to resistance 51. Since the holding path for relay I9 is also traced from ground on its own top armature 60 front contact and winding to the same resistance 51, it Will be evident that the first path traced from direct ground will shunt out the ground path through the winding of relay I9, thereby causing its release. Relay I9 in releasing at contact 56 transfers the holding of relay 20 to lead 55. Relay I9 also closes a circuit for operating holding magnet H2 over a path traced from ground on its bottom armature and back contact through contact 6| on holding magnet H1 and thence through the top Winding on holding magnet Hz to battery. When the slow releasing relay I8 releases it opens the ground path through break contact on relay I1 and the lead 55 causing relay 20 also to release and prepare the circuit control of relays I9 and 20 for the next digit. Release of relay I8 at its bottom contact also removes ground from lead 34, causing selecting magnet control relays I4 to I6 to restore to normal for use in recording the next digit. Selecting magnet S5 then'releases. When holding magnet Hz operated it caused the contact springs 21 in the bank of the switch SW to operate, due to the selecting magnet S5 being in an operated position at that time. The holding magnet H2 locks through its bottom winding and bottom make contact to ground on relay 26 and remains operated until after the registered number is no longer required.

The subscriber upon dialing the last digit 4 of the number 454 again causes relay ID to follow the contact closure of the dial and it may be assumed that relays l3 to IE function in identically the same manner as described above for the first digit of the number. At the end of these four pulses of the relay Ill, relay I1 releases again and closes a circuit from ground at contact and armature on selecting magnet S1, lead 54, top make contact relay l8, top break contact relay ll, lead 55, contact 58 and winding on relay l9, through resistance 51 to battery. Relay l9 operating closes ground at its bottom make contact through top armature and front contact relay 2!. over lead 63, through top make contact on holding magnet Hz to top winding H3 to battery. When slow-release relay l8 releases it opens the ground path at its top make contact as described above for permitting relay 29 to operate and at its bottom contact it opens the circuit previously described for restoring the selecting magnet control relay I3 to l6 to normal. The holding magnet H73 through its bottom winding and bottom make contact remains locked to the bottom break contact on relay 26 previously described.

Having thus described the registering of a three digit number 454'it can be seen that numbers with any other number of digits may likewise be registered. Usually, a cross-bar switch of ten digit capacity is employed in order to provide for additional digits to the normal subscriber number which indicate party numbers and the like. When the subscriber sender proceeds to set up the connecting switches guided by the number registered on the cross-bar switch, the sending switch 22 will be made to take one step at a time by control of the magnet 23. This switch connects the sending pulse relay 24 from battery to the leads designated 36 one at a time. When connected to the first row of contacts the sending pulse relay 24 will be operated by four ground impulses being impressed on one of the leads 3'! connected to the armature of contact springs 4 in the first row of contacts. contact 2?, pulse relay 24 will be operated by five ground impulses and again when connected to the third row at contact 28 it will be operated by four pulses. Each different one of the leads 31 supplies a different number of ground impulses corresponding to the contact springs to which they are connected. The sending pulse relay 24 thus repeats the number registered on the switch by opening and closing the contact 25 which may be made to control connecting switches in any well-known manner. v

When the registered number is no longer required the register equipment will be restored to normal by the sender causing the operation of release relay 25. This relay at its top and bottom back contacts opens the locking circuit for all holding magnets H1, H2 etc. causing them and their associated contact springs to restore to normal. At contact 62 on relay 26 ground is removed from lead 6| for restoring relays I9, 20 and 2|. Upon the further disconnection of the When connected to the second row at' sender from the line finder the circuit to the pulse relay II] will have been broken allowing the relay It to release and thereafter to release slow relay H and restoring the register circuit completely to normal.

What is claimed is:

1. In a telephone system, a cross-bar switch comprising selecting magnets and holding magnets and means responsive to the operation of a selecting magnet followed by the operation of. a holding magnet for establishing a corresponding connection in said switch, a pulsing relay, means responsive to a series of impulses from said relay for operating and releasing said selecting magnets in succession, one by each impulse and for locking the selecting magnets operated by the last impulse in each series received, and means responsive at the end of each series of impulses for operating and holding operated the succeeding holding magnet and for releasing the selecting magnet locked by the corresponding series received.

2. In a telephone system, a cross-bar switch comprising contacts arranged in horizontal and vertical rows, two sets of lines, each line of one set connected to contacts in a corresponding horizontal row, and each line of the other set connected to contacts in a corresponding vertical row, a selecting magnet for each horizontal row, a holding magnet for each vertical row, means effective on the operation of a selecting magnet followed by the operation of a holding magnet for establishing a connection at the contacts at the intersecting point between corresponding lines, a pulsing relay, sets of relays and circuit means responsive to series of impulses from said pulsing relay for operating and releasing said selecting magnets in succession, one by each impulse and for maintaining the selecting magnet operated by the last impulse received in each series, a second set of relays and circuit means responsive at the end of each series of impulses for operating and holding operated a succeeding holding magnet and release the selecting magnet locked by the corresponding series received.

3. In a telephone system, a cross-bar switch comprising selecting magnets and holding magnets and means responsive to the operation of a selecting magnet followed by the operation of a holding magnet for establishing a corresponding connection in said switch, a pulsing relay, means including two relays responsive to a series of. impulses to operate on every odd impulse and releasing on every even impulse of said series, means responsive on the succeeding alternate operations of said relays for operating and releasing succeeding selecting magnets and locking the last selecting magnet operated on the last operation or release of said relays in response to the last impulse received, means including a third relay operativeto actuate said third relay when the first impulse is received in said series and operated to release said third relay when the last impulse has been received, means including a fourth and fifth relay operative to actuate said fourth and fifth relay on the release of said third relay at the end of each odd series and to release said fourth and fifth relay on the release of said third relay at the end of each even series, and means operating in response to the operation or release of said fourth and fifth relays for operating and holding operated succeeding holding magnets and for releasing the selecting magnets locked by the corresponding series.

GERALD V. KING. 

